Datasheet

ManualsBrandsLINEAR TECHNOLOGY ManualsDev KitsPCB design board

LTM8025

8025fc

For more information www.linear.com/LTM8025

Typical applicaTion

FeaTures

applicaTions

DescripTion

36V, 3A Step-Down

µModule Regulator

The LT M

8025 is a 36V

, 3A step down µModule

(mi-

cromodule) converter. Included in the package are the

switching controller, power switches, inductor and all

support components. Operating over an

input voltage

range of 3.6V to 36V, the LTM8025 supports an output

voltage range of 0.8V to 24V and a switching frequency

range of 200kHz to 2.4MHz, each set by a single resistor.

Only the bulk input and output ﬁlter capacitors are needed

to ﬁnish the design.

The LTM8025 is packaged in a thermally enhanced, com

pact (9mm × 15mm) and low proﬁle over-molded land

grid array (LGA) and ball grid array (BGA) packages suit-

able for automated assembly by standard surface mount

equipment. The L

TM8025 is available with SnPb (BGA) or

RoHS compliant terminal ﬁnish.

L, LT, LTC, LTM, Linear Technology, the Linear logo, µModule and Burst Mode are registered

trademarks of Linear Technology Corporation. All other trademarks are the property of their

respective owners.

Complete Step-Down Switch Mode Power Supply

Wide Input Voltage Range: 3.6V to 36V

Up to 3A Output Current

Parallelable for Increased Output Current

0.8V to 24V Output Voltage

Selectable Switching Frequency: 200kHz to 2.4MHz

Current Mode Control

SnPb or RoHS Compliant Finish

Programmable Soft-Start

9mm × 15mm × 4.32mm LGA and 9mm × 15mm ×

4.92mm BGA Packages

Automotive Battery Regulation

Power for Portable Products

Distributed Supply Regulation

Industrial Supplies

Wall Transformer Regulation

Efﬁciency

OUTPUT CURRENT (mA)

100

8025 TA01b

EFFICIENCY(%)

0 500 1000 1500 2000 2500

3000

= 24V

RUN/SS

RT ADJ

OUT

GND

8025 TA01a

LTM8025

22V TO 36V

*RUNNING VOLTAGE RANGE. PLEASE REFER TO

APPLICATIONS INFORMATION SECTION FOR START-UP DETAILS

OUT

12V AT 3A

47.5k

34.8k

4.7µF

22µF

PGOOD

SYNC

AUX

BIAS

Summary of content (22 pages)

PAGE 1
LTM8025 36V, 3A Step-Down µModule Regulator Features n n n n n n n n n n Description Complete Step-Down Switch Mode Power Supply Wide Input Voltage Range: 3.6V to 36V Up to 3A Output Current Parallelable for Increased Output Current 0.8V to 24V Output Voltage Selectable Switching Frequency: 200kHz to 2.4MHz Current Mode Control SnPb or RoHS Compliant Finish Programmable Soft-Start 9mm × 15mm × 4.32mm LGA and 9mm × 15mm × 4.
PAGE 2
LTM8025 Absolute Maximum Ratings (Note 1) BIAS...........................................................................25V VIN + BIAS..................................................................56V Maximum Junction Temperature (Note 2)............. 125°C Solder Temperature................................................ 245°C VIN, RUN/SS Voltage..................................................36V ADJ, RT, SHARE Voltage..............................................6V VOUT, AUX.....................
PAGE 3
LTM8025 Electrical Characteristics The l denotes the specifications which apply over the full operating temperature range, otherwise specifications are at TA = 25°C. VIN = 12V, RUN/SS = 12V, BIAS = 3V unless otherwise noted. (Note 2) PARAMETER CONDITIONS MIN Minimum Input Voltage Output DC Voltage TYP MAX 3.6 l 0 < IOUT ≤ 3A; RADJ Open 0 < IOUT ≤ 3A; RADJ = 16.9k; VIN = 32V 0.8 24 0 UNITS V V V Output DC Current VOUT = 3.
PAGE 4
LTM8025 Typical Performance Characteristics 2.5VOUT Efficiency 100 3.
PAGE 5
LTM8025 Typical Performance Characteristics Bias Current vs Load Current 8VOUT BIAS CURRENT (mA) 50 40 30 20 100 50 40 24VIN 30 20 1000 2000 LOAD CURRENT (mA) 0 3000 8025 G10 Input Current vs Load Current 2.5VOUT 2500 2500 1000 2000 LOAD CURRENT (mA) 40 0 3000 INPUT CURRENT (mA) 1000 500 0 8025 G11 500 1000 LOAD CURRENT (mA) 1500 8025 G12 Input Current vs Load Current 5VOUT 1600 5.5VIN 12VIN 24VIN 32VIN 2000 1500 24VIN 60 Input Current vs Load Current 3.
PAGE 6
LTM8025 Typical Performance Characteristics Input Current vs Input Voltage Output Shorted 600 40 Minimum Input Voltage vs Load Current, 3.3VOUT 6.0 TO RUN TO START RUN/SS CONTROLLED 5.5 400 300 200 INPUT VOLTAGE (V) 30 INPUT VOLTAGE (V) INPUT CURRENT (mA) Minimum Input Running Voltage vs VOUT, IOUT = 3A 35 500 25 20 15 5.0 4.5 4.0 10 100 0 3.5 5 0 10 20 INPUT VOLTAGE (V) 0 30 Minimum Input Voltage vs Load Current, 8VOUT 11.0 TO RUN TO START RUN/SS CONTROLLED INPUT VOLTAGE (V) 6.5 6.
PAGE 7
LTM8025 Typical Performance Characteristics 20 Minimum Input Voltage vs Load Current, –8VOUT TA = 25°C, unless otherwise noted.
PAGE 8
LTM8025 Pin Functions VOUT (Bank 1): Power Output Pins. Apply the output filter capacitor and the output load between these pins and GND pins. GND (Bank 2): Tie these GND pins to a local ground plane below the LTM8025 and the circuit components. In most applications, the bulk of the heat flow out of the LTM8025 is through these pads, so the printed circuit design has a large impact on the thermal performance of the part. See the PCB Layout and Thermal Considerations sections for more details.
PAGE 9
LTM8025 Block Diagram VIN VOUT 8.2µH 499k 0.2µF 15pF 4.4µF AUX BIAS RUN/SS SHARE CURRENT MODE CONTROLLER SYNC GND RT PGOOD ADJ 8025 BD Operation The LTM8025 is a standalone nonisolated step-down switching DC/DC power supply that can deliver up to 3A of output current. This module provides a precisely regulated output voltage programmable via one external resistor from 0.8V to 25V. The input voltage range is 3.6V to 36V.
PAGE 10
LTM8025 Applications Information For most applications, the design process is straight forward, summarized as follows: 1. Look at Table 1 and find the row that has the desired input range and output voltage. 2. Apply the recommended CIN, COUT, RADJ and RT values. 3. Connect BIAS as indicated. While these component combinations have been tested for proper operation, it is incumbent upon the user to verify proper operation over the intended system’s line, load and environmental conditions.
PAGE 11
LTM8025 Applications Information Table 1: Recommended Component Values and Configuration (TA = 25°C) VIN VOUT CIN COUT RADJ BIAS fOPTIMAL RT(OPTIMAL) fMAX RT(MIN) 3.6V to 36V 0.8V 10µF, 50V, 1210 Open 2.8V to 25V 230kHz 182k 250kHz 169k 4× 100µF, 6.3V, 1210 3.6V to 36V 1V 10µF, 50V, 1210 1.87M 2.8V to 25V 240kHz 174k 285kHz 147k 4× 100µF, 6.3V, 1210 3.6V to 36V 1.2V 10µF, 50V, 1210 953k 2.8V to 25V 255kHz 162k 315kHz 130k 4× 100µF, 6.3V, 1210 3.6V to 36V 1.5V 10µF, 50V, 1210 549k 2.
PAGE 12
LTM8025 Applications Information Table 2. Switching Frequency vs RT Value SWITCHING FREQUENCY RT VALUE 0.2MHz 215kΩ 0.3MHz 137kΩ 0.4MHz 100kΩ 0.5MHz 76.8kΩ 0.6MHz 63.4kΩ 0.7MHz 52.3kΩ 0.8MHz 44.2kΩ 0.9MHz 38.3kΩ 1MHz 34.0kΩ 1.2MHz 26.7kΩ 1.4MHz 21.5kΩ 1.6MHz 17.8kΩ 1.8MHz 14.7kΩ 2MHz 12.1kΩ 2.2MHz 9.76kΩ 2.4MHz 8.25kΩ voltage, output voltage and switching frequency, but 4V to 5V works well in many applications.
PAGE 13
LTM8025 Applications Information whether the RUN/SS is used. As shown in the Typical Performance Characteristics section, the minimum input voltage to run a 3.3V output at light load is only about 3.6V, but, if the RUN/SS is pulled up to VIN, it takes 5.5VIN to start. If the LTM8025 is enabled with the RUN/SS pin, the minimum voltage to start at light loads is lower, about 4.3V.
PAGE 14
LTM8025 Applications Information VIN VIN VOUT VOUT RUN/SS AUX LTM8025 RT AUX GND PGOOD RT RADJ GND BIAS SYNC ADJ SYNC SHDN GND BIAS VOUT VIN 8025 F02 Figure 2. The Input Diode Prevents a Shorted Input from Discharging a Backup Battery Tied to the Output. It Also Protects the Circuit from a Reversed Input. The LTM8025 Runs Only When the Input is Present. COUT CIN GND 1. Place the RADJ and RT resistors as close as possible to their respective pins. 2.
PAGE 15
LTM8025 Applications Information Thermal Considerations The LTM8025 output current may need to be derated if it is required to operate in a high ambient temperature or deliver a large amount of continuous power. The amount of current derating is dependent upon the input voltage, output power and ambient temperature. The temperature rise curves given in the Typical Performance Characteristics section can be used as a guide.
PAGE 16
LTM8025 TYPICAL Applications 1.8V Step-Down Converter VIN 3.6V TO 24V VIN RUN/SS 10µF VOUT 1.8V AT 3A VOUT AUX 300µF LTM8025 BIAS SHARE PGOOD RT ADJ SYNC 147k GND 383k 8025 TA02 2.5V Step-Down Converter VIN* 4.1V TO 36V VIN RUN/SS 4.7µF 3.3V VOUT 2.5V AT 3A VOUT AUX 200µF LTM8025 BIAS SHARE PGOOD RT ADJ SYNC 137k GND 226k *RUNNING VOLTAGE RANGE. PLEASE REFER TO APPLICATIONS INFORMATION SECTION FOR START-UP DETAILS 8025 TA03 8V Step-Down Converter VIN* 11V TO 36V VIN 4.
PAGE 17
LTM8025 TYPICAL Applications –5V Negative Output Converter VIN* 7.5V TO 30V VIN VOUT RUN/SS AUX LTM8025 SHARE 4.7µF BIAS PGOOD RT ADJ SYNC 93.1k OPTIONAL SCHOTTKY DIODE 100µF GND 93.1k *RUNNING VOLTAGE RANGE. PLEASE REFER TO APPLICATIONS INFORMATION SECTION FOR START-UP DETAILS 8025 TA05 VOUT –5V AT 2A Two LTM8025s in Parallel, 2.5V at 5.5A VIN* 4.1V TO 36V VIN VOUT 2.5V AT 5.6A VOUT RUN/SS AUX LTM8025 SHARE BIAS 3V PGOOD 2.
PAGE 18
4 X For more information www.linear.com/LTM8025 6.350 5.080 3.810 2.540 1.270 0.000 1.270 2.540 3.810 5.080 6.350 15 BSC Y aaa Z 3.95 – 4.05 eee S X Y 0.27 – 0.37 SUBSTRATE DETAIL B DETAILS OF PAD #1 IDENTIFIER ARE OPTIONAL, BUT MUST BE LOCATED WITHIN THE ZONE INDICATED. THE PAD #1 IDENTIFIER MAY BE EITHER A MOLD OR MARKED FEATURE LAND DESIGNATION PER JESD MO-222, SPP-010 7 PACKAGE ROW AND COLUMN LABELING MAY VARY AMONG µModule PRODUCTS.
PAGE 19
0.630 ±0.025 Ø 70x 2.540 SUGGESTED PCB LAYOUT TOP VIEW 1.270 PACKAGE TOP VIEW 0.3175 0.000 0.3175 4 1.270 PIN “A1” CORNER E 2.540 aaa Z 3.810 3.810 Y For more information www.linear.com/LTM8025 6.350 5.080 3.810 2.540 1.270 0.000 1.270 2.540 3.810 5.080 6.350 D X aaa Z // bbb Z SYMBOL A A1 A2 b b1 D E e F G H1 H2 aaa bbb ccc ddd eee H1 SUBSTRATE A1 NOM 4.92 0.60 4.32 0.75 0.63 15.00 9.00 1.27 12.70 7.62 0.32 4.00 A2 A MAX 5.12 0.70 4.42 0.90 0.
PAGE 20
LTM8025 Package Description Pin Assignment Table (Arranged by Pin Number) PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME PIN NAME A1 VOUT B1 VOUT C1 VOUT D1 VOUT E1 GND F1 GND A2 VOUT A3 VOUT B2 VOUT B3 VOUT C2 VOUT C3 VOUT D2 VOUT D3 VOUT E2 GND F2 GND E3 GND F3 GND A4 VOUT A5 GND B4 VOUT B5 GND C4 VOUT C5 GND D4 VOUT D5 GND E4 GND F4 GND E5 GND F5 GND A6 GND B6 GND C6 GND D6 GND E6 GND F6 GND A7 GND B7 GND C7 GND D7 GND E7 GND F7 GND PIN NAME PIN NAME
PAGE 21
LTM8025 Revision History REV DATE DESCRIPTION A 2/10 Change to “Current Out of ADJ Operation” in Electrical Characteristics PAGE NUMBER 3 Additions to Table 1 11 Changes to “Shorted Input Protection” Section 13 Changes to Related Parts Table B 8/13 Added BGA package C 2/14 Added SnPb BGA option 20 1, 2, 19 1, 2 8025fc Information furnished by Linear Technology Corporation is believed to be accurate and reliable. However, no responsibility is assumed for its use.
PAGE 22
LTM8025 Package Photography Typical Application 3.3V Step-Down Converter VIN* 5.5V TO 36V VIN 4.7µF RUN/SS AUX LTM8025 SHARE BIAS PGOOD RT 118k VOUT 3.3V AT 3A VOUT 100µF ADJ SYNC GND 154k *RUNNING VOLTAGE RANGE. PLEASE REFER TO APPLICATIONS INFORMATION SECTION FOR START-UP DETAILS 8025 TA07 Related Parts PART NUMBER DESCRIPTION COMMENTS LTM4600/LTM4602 10A and 6A DC/DC µModule Pin Compatible, 4.5V ≤ VIN ≤ 28V, 15mm × 15mm × 2.